The extreme commercial demand for polymer based protective coatings has triggered in a recent propagation of methods expected to impart high corrosion resistance and numerous such methods involve wet-based processing of hydrophobic polymers. This work explores the feasibility of hydrophobic SiO2- poly (methyl methacrylate) (PMMA) coatings towards surface protecting applications where the undesired corrosion issue takes place on the host surface. Hydrophobic SiO2-PMMA composite coating is achieved on stainless steel (SS) substrate for different time duration of dip coating using pre-synthesized SiO2-PMMA sol by sol-gel method. Coating duration of SiO2-PMMA influences PMMA species filling at SiO2 microstructures which relay on wettability behaviour of SS surface switch from Wenzel state to Cassie-Baxter state. The underlying mechanism of water repellence on SiO2-PMMA composite surface is examined using quantum chemical calculations. It clearly demonstrates that the high dipole moment of SiO2-MMA pair (5.63 Debye), than H2O (1.85 Debye) beneficially displaces water from steel and perhaps enhances the physical adsorption between steel greatly improved the corrosion resistance. (C) 2015 Elsevier Ltd. All rights reserved.